Drill sharpening machine



July 6, 1954 w, cAw 2,682,736

DRILL SHARPENING MACHINE Filed May 3, 1950 2 Sheets-Sheet l [nvenfon- IILHSLI CA'I July 6, 1954 w, c -w 2,682,736

DRILL SHARPENING MACHINE Filed May 5, 1950 2 Sheets-Sheet 2 "llllllllnuumunlnmlmm Inventor- 1618A elm. L m

Patented July 6, 1954 UNITED STATS PATENT OFFICE DRILL SHARPENING MACHINE Wilhelm Cawi, Berlin-Steglitz, Germany, assignor to Johannes Cawi, Fulda, Germany Application May 3, 1950, Serial No. 159,762 Claims priority, application Germany May 4, 1949 9 Claims. 1

. My invention relates to machines for sharpening drills or borers, especially twist drills, and more particularly to such machines of that type in which the drill is eccentrically mounted in a rotary body to rotate therewith and in addition thereto about its own axis, the two rotational axes crossing each other in space that is neither being parallel nor intersecting each other. A machine of that type is described in the Patent No. 965,952.

The desired relative position of the rotational axes of the said body and of the drill, respectively, depends upon the diameter of the drill to be sharpened on the machine so that for sharpening drills of different diameters different machines had to be used.

The object of my invention is to avoid the said disadvantage and to provide a machine which may beused for sharpening drills of widely differing diameters. This is achieved according to my invention by providing means for varying the mutual spatial position of the rotational axes of the drill and of said body, respectively, namely for varying their mutual inclination and their mutual perpendicular distance.

The said and other objects of my invention will be more fully understood from the following specification when read with the accompanying drawing in which two embodiments of my invention are illustrated by way of example.

In the drawing Figs. 1 and 2 show in side view and in front view, respectively, the end portion of a drill and illustrate diagrammatically the two conical surfaces containing the cutting edges and the lips of the twist drill,

Fig. 3 shows a longitudinal sectional view of one embodiment of the means for varying the mutual spatial position of the rotational axes of the said body and the drill,

Fig. 4 shows a longitudinal sectional view of another embodiment of said means,

Fig. 5 shows a partial sectional front view along line 5-5 in Fig.4,

Fig. 6 shows an elevational view, partly in section, of a complete drill sharpening machine,

and

Fig. 7 shows a cross sectional view along line l--'! in Fig. 3. 7

Figs. 1 and 2 illustrate the known drill sharpening process which is also used in my machine.

The cutting edges and lips of the twist drill having other. The perpendicular spatial distance of said axes should be about d and the points of said conical surfaces should be distanced by about 1.9d from the axis of the drill. The presently used drill sharpening machines are constructed in view of this requirement and separate machines had to be used for drills of different diameters. My new machine, however, permits adjustments with regard to different diameters d and therefore can be used for sharpening drills of practically all diameters.

First referring to Fig. 6 my machine comprises a stand 13 having a desklike extension A upon which a turnable and slidable adjusting table F is mounted. This table is turnable about a pivot D and may be secured in any turned position by the screw bolt E. As shown said table may also be moved to and from the grinding disc G rotatably mounted in the machine stand B. Such movement is effected by the screw spindle K which engages said table F and which is actuated by the hand wheel L. Said table F supports a casing c which houses the holding and driving means for the chuck h. A rotating body e is rotatably supported by said casing c, and this body e is additionally supported by a shaft 1 journalled in the rear part of the casing c and engaging the member e. The shaft 1 is connected with the body e by a pin s so that the shaft 1 drives the body 6 when rotating. The shaft 1 carries at its outer end a toothed wheel f which meshes with a pinion f keyed upon ashaft rotatably mounted in said casing c and driven by a pulley f or by any other suitable means. The body e forms-the support of the drill holder g constructed in a manner known per se and carrying the chuck it. The drill holder g has a cylindrical outer surface.

According to the invention the drill holder .g is mounted in a sleeve i rotatable within the member c. This sleeve 1' may be adjusted by a latch is fixed on its front flange. This latch is fastened to the flange and may be fixed on the member e by means of a screw m. If the sleeve is to be turned the screw m is unscrewed and the sleeve adjusted by hand in the desired manner by means of the latch 70 and is then again fixed in its new position by the screw m. Certain adjusting positions are provided and therefore a corresponding number of threaded holes m are distributed around the circumference into which the screw m may be inserted. The drill holder g carries a toothed collar or ring member 11 meshing with a toothing n of a bushing o rotatable around the shaft This bushing is further connected with a shaft 7 by means of a worm gear of a helical. gearing p and may be rotated by the latter for the purpose of changing the relief grinding of the drill.

During the working of the machine the shaft f is rotated by hand or mechanically, thereby driving the member e connected with it so that the drill holder g rotates around the axis of the shaft In addition thereto, the drill holder further rotates around its own axis and in consequence thereof that the toothed wheel 11 fastened on the drill holder engages the 'toothing n of the bushing 0 which is stationary during the working of the machine. The toothings n, n are so related that the drill holder 9 executes half a rotation around its own axis during one rotation around the axis of the shaft 1; thereby after every rotation around the axis of the shaft f the surface of the drill to be sharpened and guided along the grinding disc is changed.

According to the invention the sleeve 1' is constructed in a special manner. The axis of its inner boring is arranged eccentrically to the outer cylindrical circumference, these two axes however are not parallel to each other but are inclined relatively to each other by the angle 7 v. The intersecting point of the two axes indicated in Fig. 3 of the drawing by dot-and-dash lines lies on the plane in which the toothings n, n mesh so that the meshing of the toothings remains undisturbed independent of the turning of the sleeve 1'. If the sleeve 13 is turned, the rectangular distance between the axis of the drill holder 9/ and the axis of the shaft 7 is changed as well as the inclination of said axes relatively to each other designated in Figs. 1 and 2 with 1.9cl or d/? respectively are changed. Thereby the position of the drill holder 9 relatively to the axis of rotation of the member e or the shaft ,1 may be adapted to the diameter of the drill to be sharpened. Suitably the diameters of the drills to be sharpened are divided into a number of groups in such a way, that the drills appertaining to one group may be sharpened with sufficient exactness if the bush 5 is adjusted corresponding to the average diameter of this group so that a great range of drills to be sharpened may be ground with a relatively small number of adjustments.

As the angular position of the drill holder g relatively to the shaft 1 changes with the adjustment of the sleeve z the toothing of the bevel gear n, n is constructed according to the inven tion in a special way for the purpose to ensure a correct meshing in every position. The flanks of the teeth of one or of both bulged or curved in the axial direction so that the teeth engage each other in their center if the axis of the sleeve is in its center position and this engagement is displaced towards the one or the other side if the angular position is displaced from its center position in the one or the other sense.

Instead of the said sleeve i other means may be used to attain the necessary adjustment of the two axes relatively to each other. One such further embodiment is shown in Figs. 4 and 5.

The drill holder g carries the chuck h inserted similarly to Fig. 3 into the drill holder by means of a conical pivot. In the casing c of the machine a rotating member e is provided supported by the shaft f journaled in the rear part of the casing (not shown in the drawing). The rotating member e is provided with a conical bore t diverging in the forward direction, within which the drill holder 91 may be adjusted In other words the distances wheels are in any direction. For this purpose the rear end of the drill holder is solidly connected with an annular part it being integral with a hollow ball-like portion u This portion is completed by the portion u to a hollow balllike bearing consisting of two parts to enable it to be mounted on a ball '0 arranged at the end of the rotating member 8 and being integral with it. The bearing u M3 is provided on its outer side with teeth u meshing with the toothing n of the shell 0 corresponding to the shell 0 of the embodiment according to Fig. 3. At its front end the drill holder passes through a boring of a plate in curved according to a spherical calotte. This plate slides along the front surface w of the rotating member e also shaped like a spherical calotte. When adjusting the axis of the drill holder g within the conical boring t the plate 10 slides on the surface at and may be fixed to it in any adjusted position. For this purpose screws 1/ are provided passing through borings m of the plate w. These borings are considerably larger than the diameter of the screws :4 in all directions so that the plate may move relatively to the screws in every direction. Washers a lying beneath the heads of the screws 1/ and having a larger diameter than the borings w press the plate in onto the contacting surface a: if the screws are tightened, and thereby fix the drill holder in its adjusted position.

This construction, therefore, allows an adjustment of the axes of the drill holder 9 and the rotating member 6 relatively to each other with respect to their angular position as well as with respect to their rectangular distance from each other. In the drawing a second adjusted position of the drill holder is indicated by dot-anddash lines.

During the adjustment the spherical calotte 21. 14 1& moves on the ball 22. The drill holder 9 is therefor always swung about a diameter of the ball 0 so that the toothing a n remain in engagement with each other independently of the position of the drill holder.

I claim:

arpening machine of the type overnent comprising in comng shaft; rotating naft; a drill holder eccentricaily mounted in body to rotate therewith and also rotatable about its own axis; the

onal axis of s id drill holder and the roration l axis of body crossing other in namely .er being parallel nor intersecting each ot means to vary the mutual inclination and t...e mutual perpendicular dis tance of said rotational axes; and driving means to rotate said body and said drill hoider.

2. In a drill sharpening machine of the type described the improvement comprising in combination a rotating body, an angularly adjustable sleeve mounted eccentrically in said body with its longitudinal axis inclined to the axis of rotation of said body, means to fix said sleeve in said body in different angular positions, the inner boring of said sleeve being eccentric and inclined with regard to said longitudinal. axis of the sleeve, a drill holder rotatably supported in said inner boring of said sleeve, and driving means to rotate said body and said drill holder.

3. A drill sharpening machine according to claim 2 wherein the intersecting point of the axis of the inner boring of the sleeve and of its longitudinal axis is situated in the plane in which the driving means rotating the drill holder engage the same.

4. In a drill sharpening machine of the type described the improvement comprising in combination a rotating body, an angularly adjustable sleeve mounted eccentrically in said body with its longitudinal axis inclined to the axis of r0- tation of said body, means to fix said sleeve in said body in different angular positions, the inner boring of said sleeve being eccentric and inclined with regard to said longitudinal axis of the sleeve, a drill holder rotatably supported in said inner boring of said sleeve, a stationary toothed ring member arranged coaxially and angularly adjustable with regard to the axis of rotation of said rotating body, and a second toothed ring member coaxially secured to the drill holder and adapted to engage the said stationary toothed ring member thereby rotating the drill holder about its own axis While the same is rotating with said rotating body, the

intersecting point of the axis of the inner boring of said sleeve and of its longitudinal axis being situated in the plane in which said stationary toothed ring member engages said second ring member.

5. A drill sharpening machine according to claim 1 comprising in combination a rotating body provided with a conical boring diverging in the forward direction, a drill holder adjustably arranged Within said boring, a ball and socket joint connecting the rear end of said drill holder to said rotating body at the narrower end of said conical boring, means coacting with said drill holder and being adapted to rotate the same around its own axis, and locking means adapted to secure said drill holder in adjusted positions within said conical boring.

6. A drill sharpening machine according to claim 1 comprising in combination a rotating body provided with a conical boring diverging in the forward direction, a drill holder adjustably arranged within said boring, an articulated joint connecting the rear end of said drill holder to said rotating body at the narrow end of said conical boring, means coacting with said drill holder and being adapted to rotate the same around its own axis, and locking means adapted to secure said drill holder in adjusted positions within said conical boring.

7. A drill sharpening machine as claimed in claim 6 comprising a rotating body having a spherically shaped front face curved around the center of the articulated joint, a conformingly spherically shaped plate slidingly contacting said spherically shaped front face and attached to said drill holder at least near its front end, and locking means adapted to secure said plate on said spherical surface in any adjusted position.

8. A drill sharpening machine according to claim 1 comprising in combination, a rotating body provided with a conical boring diverging in the forward direction, a drill holder adjustably arranged Within said boring and supported by said rotating member, a spherical body provided on the said rotating body at least near the rear narrow end of said conical bore, a bearing bush shaped like a hollow spherical calotte provided at the rear end of said drill holder and encasing said spherical body, means coating with said bearing bush and adapted to rotate the said drill holder around its own axis, and locking means adapted to secure said drill holder in adjusted positions within said conical boring.

9.-A drill sharpening machine as claimed in claim 4 wherein the teeth of at least one of said toothed ring members are curved in axial direction.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 270,365 Bancroft et a1 Jan. 9, 1883 490,588 Palmer et a1 Jan. 24, 1893 512,545 Gilman Jan. 9, 1894 819,173 Schmaltz May 1, 1906 965,952 Schmaltz Aug. 2, 1910 966,731 Brinkman Aug. 9, 1910 1,095,338 Mallory May 5, 1914 2,065,847 Young Dec. 29, 1936 2,217,545 Guenther Oct. 8, 1940 2,386,687 Jearum Oct. 9, 1945 2,607,172 Ruolle Aug. 19, 1952 FOREIGN PATENTS Number Country Date 306,887 Great Britain July 11, 1929 365,574 Germany Dec. 18, 1922 569,065 Germany Jan. 27, 1933 

